Vehicle outrigger pad structure

ABSTRACT

A pad structure of generally circular configuration for attachment to the stabilizing outriggers of a vehicle such as a backhoe. The structure includes a base and peripheral side wall covered with rubber. Each pad structure is mounted to its associated outrigger by a ball joint which allows the pad to rotate and also to conform to the grade of the supporting surface. The pad is resistant to wear because of the rubber material, because of its configuration, and because of its capacity for rotation. Instead of dragging and digging into the supporting surface and adjacent structures, such as curbs and the like, it moves and thereby continually presents new wearing surfaces. Other features include means enabling ready removal and replacement of worn pads.

United States Patent [191 Moore Aug. 27, 1974 VEHICLE OUTRIGGER PADSTRUCTURE Harold K. Moore, 4833 Dunrobin Ave., Lakewood, Calif. 90713Filed: Oct. 5, 1973 Appl. No.: 404,092

Inventor:

US. Cl. 212/145, 248/24 Int. Cl. B66c 23/62 Field of Search 212/145;254/86 R; 188/7;

References Cited UNITED STATES PATENTS 3/l962 Kramcsak, Jr. et a].254/86 R 10/1966 Noller 212/145 ABSTRACT A pad structure of generallycircular configuration for attachment to the stabilizing Outriggers of avehicle such as a backhoe. The structure includes a base and peripheralside wall covered with rubber. Each pad structure is mounted to itsassociated outrigger by a ball joint which allows the pad to rotate andalso to conform to the grade of the supporting surface. The pad isresistant to wear because of the rubber material, because of itsconfiguration, and because of its capacity for rotation. Instead ofdragging and digging into the supporting surface and adjacentstructures, such as curbs and the like, it moves and thereby continuallypresents new wearing surfaces. Other features include means enablingready removal and replacement of worn pads.

5 Claims, 4 Drawing Figures BACKGROUND OF THE INVENTION ground orroadway as the backhoe progressively advances along a predetermineddigging path. Often the digging is closely adjacent a street curb or thelike and the commonly used rectangular steel plates which are used forthe outrigger pads strike against the curb and break it up so that ithas to be replaced. The dragging sharp cornered plates also often tearup street surfaces so that they too have to be replaced.

SUMMARY OF THE INVENTION According to the present invention, anoutrigger pad structure is provided for attachment to the end of each ofthe usual outriggers that are used to support and stabilize a vehiclesuch as a backhoe. The pad structure comprises a foot having a base anda generally circular peripheral side wall over which is fitted aresilient pad. The pad is anchored in position on the wall by surfaceprotrusions such as ribs or the like provided on the wall. The foot isconnected to its outrigger by a ball joint assembly operative to permitthe foot to pivotally conform to the grade of the road or othersupporting surface, and further operative to permit the foot to rotateabout a generally vertical axis. With this arrangement the resilient paddoes not tear up or destroy the roadway or adjacent street curbs or thelike. Instead, the pivotal conformation of the pad to the roadway tendsto wear the pad more evenly; there are no sharp corners to dig into theroadway; and, as the pad is dragged over the roadway, or strikes a curb,it tends to rotate, presenting new wearing surfaces, reducing abrading,and making it easier to advance the backhoe on the dragging outriggerpads.

The forces acting upon the pad tend to strip the pad off the foot.According to the present invention, the pad is preferably adhesivelybonded to the foot, and the peripheral wall of the foot is provided withsurface protrusions such as ribs or the like to reduce the side shearloads on the adhesive bond.

The present outrigger pad structure also includes a ball joint whichutilizes an annular collar overlying the ball to increase the bearingarea. The collar is associated with a releasable lock means such as asnap ring which allows the collar to be quickly removed so that a wornpad can be easily replaced.

Other objects and features of the invention will become apparent fromconsideration of the following description taken in connection with theaccompanying drawing.

DESCRIPTION OF THE DRAWING FIG. I is a side elevational view of abackhoe mounted on a tractor, only a portion of the tractor beingillustrated;

FIG. 2 is a partial front elevational view of the backhoe of FIG. I,particularly illustrating the pair ofoutriggers;

FIG. 3 is an enlarged view taken along the line 3-3 of FIG. 2; and

FIG. 4 is an enlarged view taken along the line 44 of FIG. 3.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings, there is illustrated a usual and conventional backhoe 10attached to a vehicle or tractor 12. The backhoe 10 includes a bucket 14attached by a bucket linkage 16 to an elongated dipstick 18. Thedipstick in turn is connected by an element 20 to a boom 22 which ismounted to the backhoe frame for pivotal movement about a generallyhorizontal axis. This axis is defined by a pivot pin 24, as best seen inFIG. 1. As is well known to those skilled in the art, selectiveoperation of a lift cylinder 26 and a crowd cylinder 28 manipulates thebucket 14 in a digging operation. i

During digging, the backhoe 10 is stabilized and supported by a pair ofstabilizers or outriggers 30 which are pivotally connected at theirupper extremities to the backhoe frame. The lower extremity of eachoutrigger 30 includes an outrigger pad structure and each outrigger 30is raised and lowered by operation of an outrigger cylinder 34. Thepresent invention is concerned with a particular pad structure 32.

More particularly, in a typical backhoe operation, the operator alignsthe tractor 12 along a predetermined digging or work path and thenactuates the outrigger cylinders 34 so that the padstructures 32 engagethe supporting surface or roadway 36. Then, by operating the cylinders26 and 28, the operator lowers the bucket 14 and scoops out a bucketfulof earth. After raising the bucket 14, the backhoe I0 is pivoted to oneside or the other to dump the excavated material. This operation isrepeated until a hole is dug of the desired depth.

Next the backhoe is advanced, that is, moved to the left, as viewed inFIG. 1, to enlarge the hole to form, for example, a trench for a drainline or the like. Al-

though it is possible to do this by actuating the cylin-' ders 34 toraise the pad structures 32 out of engagement with the roadway 36, andthen rolling the backhoe to the left, this is not normally done becauseit takes too much time. Instead, the operator lowers the boom 22 untilthe element 20 rests upon the bottom of the trench. This has the effectof raising the backhoe slightly and pushing it to the left, as viewed inFIG. 1, moving the tractor l2 and dragging the pad structures 32 overthe supporting roadway 36. When the cylinder 26 is extended to itsmaximum, theadvancement of the backhoe stops and its weight is againsteadied by the outriggers 30. The digging phase :is repeated, and thiscycle continued until the trench is finished. The progressiveadvancement of the backhoe 10 which occurs during this operationrepeatedly drags the pad structures 32 over the roadway 36.

In the prior art the outrigger pads were generally rectangular steelplates which often had only one axis of pivotal movement and weretherefore incapable of confonning to the grade of the roadway 36.Consequently, their sharp corners and edges would dig into the roadway36 and damage it so that expensive replacement was required. Moreover,where adjacent structures such as curbings were very close. the priorart pad plates often struck and damaged such curbs so that they too hadto be replaced.

In contrast to such prior art pads, the present pad structure 32comprises, as best seen in FIGS. 3 and 4, a foot 38 made of toughmaterial such as steel and having a generally circular base 40, agenerally cylindrical peripheral side wall 42 and a central hub 44. Aplurality of radial strengthening ribs 46 extend between the hub 44 andthe side wall 42.

The side wall 42 is provided with a plurality of surface protrusions inthe form of elongated, circumferentially spaced, and generallyvertically extending ribs 48.

The pad structure 32 also includes a resilient pad 50 fitted over thebase 40 and the side wall 42. The pad 50 is preferably made of rubberadhesively bonded to the foot 38 in close conformity with the ribs 48.The pad 50 is thus anchored to the ribs 48 so that shear loads imposedupon the pad 50 tend to be assumed by the ribs 48. This helps topreserve the adhesive bond and greatly reduces the incidence ofstripping or tearing away of the pad 50 from the base 40 and side wall42. It has been found in actual use that without the presence of theribs 48 or equivalent anchoring surface protrusions. the hard use andrough treatment to which backhoe outrigger pads are subjected causes anaccelerated failure of the adhesive bond between the pad 50 and the base40 and side wall 42.

As seen in FIG. 2, the usual outrigger 30 is provided with a U-shapedswivel 52 at its end for pivotal movement of the conventional pad abouta single axis defined by a transverse pin 54. In contrast, the presentpad structure 32 is "universally" movable, that is, about many axes, andfor this purpose comprises a mounting stud 55 whose upper end is rigidlysecured by any suitable means (not shown) to the base of the U- shapedswivel 52, and whose lower end includes a spherical ball 56. The ball 56forms part of a ball joint assembly which connects the pad structure 32to the outrigger swivel 52.

The hub 44 includes an upwardly opening cylindrical cavity 58 having ahemispherical socket 60 in its bottom wall. The lower hemisphere of theball 56 is seated in the socket 60 and is maintained in the socket 60 byan annular collar 62. The collar 62 is closely received within thecavity 58 in surrounding relation to the ball 56 and includes an innerannulus which is curved to fit in close conformity to the sphericalcontour of that portion of the ball 56 located just above the socket 60.In effect, the collar serves as a continuation of the socket 60 andprovides extra bearing area.

The ball 56 is free to universally" pivot within the socket 60 andwithin the socket continuation formed by the collar 62. The open area ofthe cavity 58 above the collar 62 permits the foot 38 to pivot a greateramount before it engages the stud 55. Consequently, the pad structure 32is able to accommodate steeper grades compared to prior art pads. andthe increased bearing area provided by the collar 62 gives the addedsupport needed in such situations.

The collar 62 is retained in operative position by releasable lock meansin the form of a usual snap ring 64 which engages upon the upper outerperiphery of the collar 62. The ring 64 is received with an annularretaining groove 66 in the hub 44. When it is necessary to remove thefoot 38, perhaps to remove a worn pad and recap the foot with anotherpad, the snap ring 64 is quickly removable to allow the foot 38 to dropoff the collar 62 and the stud ball 56.

The capability of the ball 56 for movement in virtually any directionpermits the foot 38 to pivotally conform to the grade of the supportingroadway 36, and further permits the foot 38 to rotate about thelongitudinal axis of the mounting stud 55. Therefore, the present padstructure is ideally suited to a backhoe operation in which the backhoedigs, slides forward, digs, and slides forward in a high-productionsequence, without raising the outriggers. That is, the resilience of thepad structure 32 resists wear, the rounded configuration does not diginto and tear up roadways and curbs and, being able to rotate, the padcontinually presents new wearing surfaces, thereby reducing any tendencyof the pad to wear in one place, and reducing the dragging friction whenthe backhoe is successively advanced. The backhoe tends to roll on therotating pads, as well as on the tractor wheels. In addition, theprovision of shear bearing surface protrusions on the foot greatlyreduces the tendency of the pad to be stripped away under high shear andimpact loads, and the provision of the ball socket joint allows the footto be quickly removed for replacement of worn pads and the like.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention.

I claim:

1. In a vehicle having a plurality ofoutriggers to support and stabilizethe vehicle during the intervals when the vehicle is stationary betweenprogressive advancements of the vehicle along a predetermined work path,an improved outrigger pad structure on each of said outriggerscomprising:

a foot including a generally circular base and a generally cylindricalperipheral wall, said wall having a multiplicity of surfaceprotrusions",

a resilient pad fitted over and bondedto said base and said wall andanchored in position on said wall by said surface protrusions; and

ball joint means connecting said foot to the outrigger and operative topermit said foot to pivotally conform to the grade of the supportingsurface, and further operative to permit said foot to rotate about agenerally vertical axis.

2. Outrigger pad structure according to claim I wherein said pad is madeof rubber adhesively bonded to said foot.

3. Outrigger pad structure according to claim 1 wherein said surfaceprotrusions comprise a plurality of elongated, circumferentially spaced,and generally vertically extending ribs.

4. Outrigger pad structure according to claim 1 wherein said ball jointmeans comprises means on said foot defining a centrally locatedhemispherical socket; a mounting stud sttached to the outrigger andhaving a spherical ball portion received in said socket; a collar insurrounding relation to said ball portion and retaining said ballportion in said socket; and releasable lock means securing said collarin said surrounding relation.

5. Outrigger pad structure according to claim 1

1. In a vehicle having a plurality of outriggers to support andstabilize the vehicle during the intervals when the vehicle isstationary between progressive advancements of the vehicle along apredetermined work path, an improved outrigger pad structure on each ofsaid outriggers comprising: a foot including a generally circular baseand a generally cylindrical peripheral wall, said wall having amultiplicity of surface protrusions; a resilient pad fitted over andbonded to said base and said wall and anchored in position on said wallby said surface protrusions; and ball joint means connecting said footto the outrigger and operative to permit said foot to pivotally conformto the grade of the supporting surface, and further operative to permitsaid foot to rotate about a generally vertical axis.
 2. Outrigger padstructure according to claim 1 wherein said pad is made of rubberadhesively bonded to said foot.
 3. Outrigger pad structure according toclaim 1 wherein said surface protrusions comprise a plurality ofelongated, circumferentially spaced, and generally vertically extendingribs.
 4. Outrigger pad structure according to claim 1 wherein said balljoint means comprises means on said foot defining a centrally locatedhemispherical socket; a mounting stud sttached to the outrigger andhaving a spherical ball portion received in said socket; a collar insurrounding relation to said ball portion and retaining said ballportion in said socket; and releasable lock means securing said collarin said surrounding relation.
 5. Outrigger pad structure according toclaim 1 wherein the vehicle is a backhoe.